Rigid blood reservoirs have been used as part of an extracorporeal circulatory support circuit for many years in order to hold venous blood drained from a patient during heart bypass surgery and/or to hold blood scavanged from the surgical field during such surgery. Examples of rigid blood reservoirs are shown in coassigned U.S. Pat. Nos. 5,149,318; 5,152,964; 5,254,080; 5,282,783; 5,304,164 and 5,403,273. Rigid blood reservoirs of this type have been available under the trade designation "SARNS.TM." venous reservoir and integral venous/cardiotomy reservoir from Minnesota Mining and Manufacturing Company, St. Paul, Minn.
For purposes of the background of this invention, many prior rigid blood reservoirs came in two types: (1) reservoirs having top mounted venous blood inlets, and (2) reservoirs having bottom mounted venous inlets. A top inlet reservoir typically includes a tubing connector mounted on the top of the reservoir, with an internal tube extending downwardly from the connector into the chamber defined by the reservoir. A bottom inlet reservoir includes a tubing connector mounted on the bottom of the reservoir, with blood entering the reservoir through the floor of the blood chamber. The blood reservoirs available under the trade designation "SARNS.TM." have included both bottom and top mounted venous blood inlets. See, e.g., U.S. Pat. Nos. 5,282,783 and 5,403,273.
There is a need for a blood reservoir in which a single venous blood inlet can function as both a bottom and top type inlet. This would allow one connection to be made to the venous inlet, while permitting the blood reservoir to be converted during use between the top and bottom venous inlet types. For example, the reservoir could be used as top inlet type during surgery, and converted to a bottom inlet type after surgery to facilitate draining the reservoir through the venous inlet. In addition, such a reservoir inlet would provide a visible inlet drop tube so that the perfusionist can observe the blood flowing in the inlet, and have the visual reassurance that the inlet tube will remain primed.
Generally, the reservoir of the invention comprises a housing having top, bottom and side walls defining a chamber inside the housing for holding fluid. An outlet is provided adjacent the bottom of the housing for draining fluid from the bottom of the chamber. The outlet has a connector for connecting tubing in fluid communication with the outlet. A novel inlet tube is connected to the housing outside the housing for supplying fluid to the chamber. The inlet tube comprises an elongate tube having a resiliently-flexible portion connecting the inlet tube in fluid communication with the chamber at or adjacent the bottom of the chamber and a free end opposite the resiliently-flexible portion. The free end of the inlet tube has a connector for connecting tubing in fluid communication with the inlet tube. A holding means is provided for releasably holding the inlet tube in a first position, in which the inlet tube is held in a generally vertical orientation generally adjacent the side wall of the housing. The inlet tube has a length that brings the connector of the inlet tube into generally close proximity with the top of the housing when the holding means holds the inlet tube in its first position. The blood reservoir can be converted between top and bottom inlet configurations by moving the inlet tube between its first position and other positions in which the inlet tube is not held by the holding means.
Preferably, the side wall of the housing has a generally vertically extending channel formed therein for releasably receiving the inlet tube. For example, the side wall has a channel-forming portion having a generally U-shaped horizontal cross section.
Most preferably, the inlet tube is formed of generally transparent material, allowing visual observation of blood flowing through inlet tube.
Also, preferably, the holding means comprises means for releasably grasping the inlet tube generally adjacent the top of the housing. For example, the means for releasably grasping may comprise a resilient clip.
Preferably, the connector at the free end of the inlet tube includes a swivel-type connection means.
Also, preferably, the inlet tube comprises a main portion extending between the resiliently-flexible portion and the connector, the main portion of the inlet tube being formed of generally rigid material.
Most preferably, the inlet tube may be moved between its first position to a second position, in which the connector of the inlet tube is positioned at a lower elevation than the bottom of the reservoir to drain the reservoir through the inlet, and to a third position, intermediate the first and second positions, in which the inlet tube extends upwardly at an angle to the vertical.
In another aspect of the invention, the blood reservoir, which may or may not include the visible inlet tube, generally comprises a housing having top, bottom and side walls defining a chamber inside the housing for holding fluid. A blood defoaming medium is provided within the chamber, with the blood defoaming medium defining an antechamber holding blood before it passes through the blood defoaming medium, and a blood storage portion of the chamber outside the blood defoaming medium for storing defoamed blood. An outlet is provided adjacent the bottom of the housing for draining fluid from the bottom of blood storage portion of the chamber. The outlet has a connector for connecting tubing in fluid communication with the outlet. An inlet is provided adjacent the bottom of the housing for supplying fluid to the chamber. The inlet has a connector for connecting tubing in fluid communication with the inlet, and an inlet opening through the bottom wall of the reservoir into the antechamber. A novel diverter cone is held concentrically over the inlet opening, and tapers downwardly in the direction toward the inlet opening. The diverter cone diverts blood entering the chamber via the inlet generally radially outwardly.
Preferably, the inlet includes a generally funnel-shaped inlet portion adjacent the inlet opening to decelerate venous blood flowing in the inlet potion before the blood enters the antechamber of the reservoir.
Also, preferably, a mounting vane extends upwardly from the bottom wall of the housing into the antechamber for holding the diverter cone in concentric position over the inlet opening. The mounting vane is most preferably radially aligned with respect to the diverter cone.
Further details of the invention are defined in the features of the claims. These and other features and advantages will be pointed out hereinafter.